Puzzle: How many hens for 6 eggs in 6 days?

Puzzle: If a hen and a half lay an egg and a half in a day and a half then how many hens will it take to lay six eggs in six days?

Answer: A simple one...right? Only 1.5 hens will be needed in this case.

Since, 1.5 eggs in 1.5 days require 1.5 hens
=> 1 egg in 1.5 days will require 1.5/1.5 = 1 hen
=> 1 egg in 1 day will require 1 * 1.5 = 1.5 hens
=> 6 eggs in 1 day will require 1.5 * 6 hens
=> 6 eggs in 6 days will require 1.5 * 6 / 6 = 1.5 hens